The Science of Life

These are the sources for my video on the scientific definition of the term chemical, seen here . The colloquial definition of the word chemical comes from wiktionary , which defines chemicals as "an artificial chemical compound".  There is of course a negative conotation about the definition seen in the example they provide (" I color my hair with henna, not chemicals ").  The non-colloquial, scientific definition of the word chemical comes from three text books: “Biology: A Guide to the Natural World Fifth Edition”; David Krogh; 978-0-321-61655-5; p. 22 “Chemistry: The Central Science 11th Edition”; Theodore L. Brown; 978-0-13-600617-6; p. 5 “Essentials of Geology 4th edition”; Stephen Marshak; 978-0-393-91939-4; p. 7 They all agree that a chemical is “matter that has distinct properties and a constant composition that does not vary from sample to sample and cannot be separated by physical means.”

The Full on definitions of the word theory from the five texts referenced in my Theories video.  The citations are in the format ("Title"; Principle Author (there may or may not be secondary authors); ISBN; page number referenced; which UNLV course the book is for).   See the video here . These books may be obtained through any public library or digitally through your  favorite  means of obtaining digital copies of books. (“Biology: A Guide to the Natural World Fifth Edition”; David Krogh; 978-0-321-61655-5; p. 6; for UNLV's course BIOL 189 - Fundamentals of Life Sciences) It is unfortunate but true that the word theory means one thing in everyday speech and something almost completely different in scientific communication. In everyday speech, a theory can be little more than a hunch. It is an unproven idea that may or may not have any supportive evidence. In science, meanwhile, a theory is a general set of principles, supported by evidence, that expla...